Downhole isolation of zones within a wellbore for fracturing treatment is well known. While the isolation of zones of interest for high pressure fracturing is an effective production methodology, there is a continuing need to improve the reliability and efficiency of tools used in the isolation and fracturing processes.
Current straddle packer designs are based primarily on cup technology which has many disadvantages. For example, straddle packers of this design are limited with respect to the depth and pressure conditions that they can operate under. In addition, they are not suitable for highly deviated or horizontal wells with complex profiles.
Furthermore, current designs of straddle packers tend to be primarily mechanical or a combination of mechanical/hydraulic. Many designs are mechanical interlocking slips or dropped balls to synchronize and control packer operation. These types of devices however, are prone to contamination within the operating environment from contaminants such as sand which can enter the devices and cause the devices to fail.
Further still, current designs are prone to problems from operator error where manipulation of the tool and tubing string may result in improper setting, operation or release of the tool white downhole.
Further yet, the retrievablility of packer tools is also particularly important. As is known the cost of both the tool and/or the time associated with attempting to retrieve a jammed tool are significant. As a result, there is a continuing need to design tools that minimize the risk of the tool becoming jammed downhole which will result in operator expense from lost time or a lost tool Furthermore, in that traditional devices generally have only one method of retrieval, there is also a need for tools which have a variety of retrieval methods such that if one method of retrieval fails, other retrieval methods are possible.
It is therefore an object of the present invention to provide a straddle isolation packer that obviates or mitigates the above disadvantages.